Supplemental Guidance on Face Coverings

Updated October 1, 2021

NOTE: This Guidance supplements the Policy on Face Coverings reinstated as of August 11, 2021. 

Extension of Face Coverings Policy

September 10, 2021: The current policy requiring all members of the campus community, whether fully vaccinated or not, to wear face coverings indoors will continue until further notice. Although the positivity rate among the campus community since the resumption of on-campus operations and in-person instruction has remained in the low to moderate range, the analysis team, composed of physicians, scientists, and administrators, recommended continuing to require masks indoors in University buildings given the high case rate in the surrounding area, the predominance of the Delta variant In Mercer County,  and other factors. The analysis team will review data and campus conditions weekly and will recommend an update to this policy as appropriate.

Face coverings are required inside buildings occupied by Princeton University with a few exceptions, including:

  • When alone in a room or cubicle. See the policy for the definition of a cubicle.
  • Residents of University student housing, when in their own living space.
  • While actively eating or drinking.
  • During classroom instruction, in accordance with the rules for Face Coverings in Classrooms, below. This exception does not extend outside of the classroom during instruction. It does not apply to meetings, office gatherings, student activities, etc.

Face Coverings in Classrooms 

September 10, 2021 The rules for face coverings in classrooms continue as established on August 23, 2021 and as outlined below for reference. Although the positivity rate among the campus community since the resumption of on-campus operations and in-person instruction has remained in the low to moderate range, the analysis team recommended continuing to require masks indoors in University buildings given the high case rate in the surrounding area, the predominance of the Delta variant In Mercer County,  and other factors.  The analysis team will review data and campus conditions on an ongoing basis and will recommend an update to this policy as appropriate.

The following rules apply for face coverings in classrooms:

  • Instructors who are fully vaccinated may remove their mask for all or part of the class at their own discretion.  Six feet of distance between unmasked faculty and students is best, when circumstances permit.
  • Students/participants must wear masks throughout the class.  If the instructor finds it necessary for a fully vaccinated student to remove their mask for a short period of time, the instructor may permit (but not require) a student to remove their mask, as long as only one student has their mask down or off at any one time.
  • For classes in which 12 or fewer students are enrolled, the instructor may decide whether fully vaccinated students should be allowed (but not required) to remove their masks for all or part of the class.

For all classrooms, lectures, and events:

  • Instructors may not require a student to remove their mask.
  • Instructors may require all students to wear masks even if the mask policy does not require all students to do so.
  • For classes with more than 12 students, instructors may not establish rules that are not consistent with this policy, even if the students in the class support those rules. For example, an instructor may not decide that fully vaccinated students in a class of 25 may remove their masks for the entire class time even if the entire class agrees to that proposal.
  • No eating in class. Individuals may lift their mask briefly to drink. 
  • Instructors who remove their mask must be fully vaccinated and participate in the University asymptomatic testing program. Visiting instructors must be fully vaccinated and must have a negative test within 48 hours of instruction.
  • Slit masks, bell covers, and drip pads effectively reduce the higher risk posed by wind instruments and must be used for rehearsals and classroom instruction. For performances and non-classroom activities, see Current Guidelines for Aerosol-Producing Performing Arts Activities.
  • Singing masks and clear masks effectively reduce the higher risk posed by singing and must be used for rehearsals and classroom instruction. For performances and non-classroom activities, see Current Guidelines for Aerosol-Producing Performing Arts Activities.
  • Consider clear masks when seeing facial expressions, mouth movements, etc. is necessary or beneficial.
  • Face shields are not substitutes for masks; however, they do offer additional protection compared to not wearing a mask and are available through EHS.
  • Disposable procedure masks (not KN95 or N95) do not significantly affect the volume or clarity of speech compared to cloth or other disposable masks.

Important Information when making decisions about face coverings in classrooms:

The Delta variant accounts for more than 95 percent of the cases on campus and in the county, and nearly all of the of the individuals testing positive on our campus are fully vaccinated. The US Centers for Disease Control (CDC) confirms that fully vaccinated individuals may spread the virus to other vaccinated or unvaccinated individuals.

Even if a person who tests positive is experiencing no symptoms or is experiencing mild illness, they still must self-isolate for at least 10 days, missing several days of in-person classes.

Face Coverings for Events, Gatherings, Lectures:

Per the Guidance for Events and Gatherings, General Guidelines for All Indoor Conferences and Events:

Event speakers may remove their masks while speaking at the event as long as only one speaker has their mask removed at any one time and there is at least 8 feet of physical distance between the speaker and other speakers or participants, as long as this is consistent with the rules for classroom instruction according to the current Supplemental Guidance for Face Coverings .

Why require face coverings for everyone?

In consideration of the entire campus community and the greater Princeton community, the University implemented the requirement for everyone, vaccinated or not, to wear face coverings indoors.

While over 95% of our campus community is fully vaccinated, scientists have confirmed that fully vaccinated individuals can contract and spread the Delta variant, which spreads twice as easily as the variants that were present back in January.  During this period of high prevalence in Mercer County and New Jersey, we are being attentive to the needs of the larger community.

Because the Delta variant spreads easily, our students live and study in congregate settings, and there is currently substantial community spread in Mercer County, we also anticipate a fair number of positive asymptomatic test results. Continuing the face coverings requirement during this period will help us limit transmission and the attendant disruption to those testing positive, who must isolate for 10 days even if they do not experience any symptoms or suffer only mild to moderate symptoms. 

The CDC and the State of NJ recommend face coverings indoors in areas where there is substantial incidence of disease. While our campus continues to have a low to moderate positivity rate, the case rate in Mercer County is high, meeting the criteria for the recommendation.  Since we have some crowded conditions and because it is not always obvious who is and is not vaccinated, this CDC and NJ recommendation is appropriate.

Why don’t the rules for classrooms apply to other areas and situations?

The masking rules for classrooms make allowances for pedagogical reasons and in support of the University’s critical teaching mission. Along with many other colleges and universities, Princeton recognizes the potential challenges of teaching while wearing a mask, especially in small classes. 

The robust and spontaneous discussion that we value in precept and seminar may be inhibited by masks, which obscure facial expressions and other non-verbal communication styles. Allowing one student to remove their mask briefly when speaking might require students to constantly be removing and replacing their mask, thereby reducing the intended protection. 

Classes that choose to take advantage of these exceptions face an additional risk of COVID-19 transmission. To minimize the risk across the campus, it is in the best interest of the campus to limit mask-wearing exceptions to the classroom.


When is it permissible to remove face coverings for eating and drinking?

You must remove your mask to eat, and removing your mask elevates the risk for COVID-19; thus, it is important to minimize the time your mask is removed for eating and drinking and wear your mask at other times indoors to minimize the overall risk. As a general recommendation, when considering providing food or allowing eating at meetings, gatherings, etc., keep in mind that being in a room with individuals who are not wearing masks may be too much of a risk for some people, and ensure that there are ways that individuals can participate without being in the space.

Meetings and Events

Food is allowed, even at indoor events.

  • Set a time for dining. Keep the time without masks as short as possible.
    • Example: Having lunch scheduled for noon to 12:45 p.m. encourages participants to put their masks back on at the end of the meal time. 
  • Have an option to take the food to a different location so that people who are at higher risk or are uncomfortable do not have to be around people who are not wearing masks.
  • Have an option to participate remotely, if possible.
  • If the meeting is mandatory and remote participation is not possible, consider not allowing food or separating the meal time from the mandatory meeting time.

Dining Halls

Only individuals who participate in the campus asymptomatic testing program or are approved visitors with a ticket to the dining hall may spend time in and eat in dining halls.

  • Diners must wear their face covering when walking around the dining hall and when in the food service area.
  • Diners should replace their face covering when they have finished the meal, even if they remain seated while others finish their meals.

Offices and Work Areas

In shared spaces, keep the time without a mask to a minimum.

  • Briefly lifting a mask to take sips of a drink poses little risk and should be allowed in any work situation.
  • Individuals in private offices or cubicles are allowed to remove their masks whenever they are alone in the room, including for eating.
  • For shared spaces where individuals are required to wear masks, consider establishing a room or area for eating.
  • If no other option is available, eating at the assigned space is allowed. Individuals who remove their mask while eating should keep the time without a mask to a minimum, and should replace it as soon as finished.
  • It is not permissible to keep a mask off for extended periods of time while intermittently snacking.

Classes and Seminars

  • No eating in class. Individuals may lift their mask briefly to drink. 

When will the policy change?

We do not know.  An analysis team will evaluate this indoor face covering requirement on an ongoing basis and will recommend changes, if any, to the policy, including relaxation or addition of requirements. They will consider the positivity rate, transmission rate, evidence of clusters of cases related to classroom instruction or other activities, the case rates in the surrounding community, variants, and other factors when making recommendations. They are unlikely to make a recommendation for change based on a single week’s data.

Do masks really work?

There are numerous peer-reviewed studies that confirm that masks, even cloth masks, are effective in reducing the spread of COVID-19.

Tight-fitting face coverings, whether reusable cloth masks or disposable, protect others from potentially infectious droplets that might be generated by the person wearing the mask, and protect the person wearing the mask. This is particularly important because people can spread the virus that causes COVID-19 without showing any symptoms.

The following CDC resources provide guidance and scientific background:

This article provides links to several peer-reviewed studies:

How will this policy be enforced?

The policy will be enforced just as it was during the months it was in place prior to July 4.

Enforcement is a community effort. Any member of the Princeton University community can do their part by

  • Intervening directly. If you see someone not wearing a mask, ask if they need one and where to find one. Point out that masks are required. If they are wearing their mask incorrectly, politely ask them to fix it.
  • Reporting the non-compliance to the individual’s department or supervisor.
  • Reporting via the EthicsPoint hotline, providing actionable information (names, locations, etc.).

Students found to be in violation of this policy may be subject to discipline in accordance with Rights, Rules, Responsibilities. Faculty and staff found to be in violation of this policy may be subject to disciplinary actions in accordance with appropriate University policy. Campus visitors found to be in violation of this policy may be subject to University sanctions including being banned from campus.

Obtaining Face Coverings

Departments may request face coverings through the EHS COVID-19 PPE & Supply Request Form.

More Information

For more information about face coverings, please refer to: